Heating, ventilation, and air conditioning (HVAC) systems typically employ a network of ducts throughout a home or building to move temperature controlled air in an effort to maintain a set temperature. Certain contemporary systems can also employ one or more dampers positioned at various locations within the ducts to govern the flow of air therethrough.
Conventional dampers are typically employed in multi-zone HVAC systems to facilitate the independent temperature control of each zone. A typical damper acts generally like a valve member within the duct in that it selectively restricts the flow of air through the duct. The above dampers can be manually or mechanically actuated. In either case, the damper is rotatable about a shaft to change an angular orientation of the damper within the duct to ultimately increase or reduce a flow restriction.
In the case of mechanically actuated dampers, a damper actuator is typically mounted to the shaft of the damper to rotate the damper to various angular orientations. The shaft of the damper extends through an exterior of the duct. The damper actuator mounts to the shaft at the exterior of the duct.
Conventional damper actuators typically include a housing that carries a motor and a gear train mechanically coupling the motor to a rotatable clamp. The motor and gear train are located within the housing. The clamp is coupled to the gear train within the housing, but the portion of the clamp used to connect the actuator to the damper shaft is located outside of the housing.
Unfortunately, clamping the damper shaft at the exterior of the housing of the actuator creates several problems. First, the input torque supplied by the motor via the gear train is applied to the clamp inside the housing. However, the clamp is fixedly connected to the shaft outside the housing. As a result, the portion of the clamp that connects to the shaft is not in the same plane as the portion of the clamp where the input torque is applied. This out of plane configuration creates a reaction force that causes the actuator to rock or oscillate in a direction generally parallel to the axis of rotation of the shaft.
Second, locating the clamp outside of the actuator creates a safety risk. A typical clamp is generally not regular in shape, and the clamp may entangle the lead wires of the actuator or other items in proximity to the clamp. As such, there is a need in the art for an actuator that provides a more balanced loading and reduces the risks of entanglement of prior designs.
The invention provides such an actuator. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.